Trailer jack



F. G. TAYLOR Oct. 3, 1967 l TRAILER JACK Filed Oct. 8, 1965 ATTORNEY United StatesA dPatent O 3,345,038 TRAILER JACK Frederick George Taylor, 21 Rose Ave., Droitwich,

Eng an Filed Oct. 8, 1965, Ser. No. 494,099 6 Claims. (Cl. 254-86) ABSTRACT F THE DISCLOSURE The present invention involves a jack having an operating screw and a carriage slide designed to move therealong. A supporting leg as well as struts are pivotally connected to the carriage slide and the struts are also pivotally connected to the vehicle on which the jack is mounted. As the carriage slide moves along the operating screw, the leg and struts are either moved to a collapsed position or to an active supporting position.

The invention has a device which will permit the carriage slide to be locked into or out of engagement with the operating screw thus enabling the carriage slide to move freely along said screw or to be locked into operative position therewith.

The present invention provides numerous advantages over other vehicle jacks of the prior art, such as simplicity in design and ease in operation, the former creating great savings in production costs and the latter adding considerable commercial Value to the invention. Other advantages are inherent in the applicants invention and will become apparent as the description proceeds.

In the applicants British Patent `890,651 published Mar. 7, 1962, a caravan jack is described wherein a screw is rotatably mounted in a vehicle mounting structure. A carriage is positioned on said screw and carries therein a half nut which is adapted to engage the screw. The nut in turn is attached to a lever which will pivot on a shaft at the opposite end of the carriage. Thus upon rotation of the shaft the lever is engaged which in turn forces the half nut into engagement with the screw. The screw then is rotated until the leg structure pivotally connected to the carriage is in the desired supporting position.

The above described jack is subject to some criticism since there exists the possibility that the shaft may rotate at an undesirable time thereby releasing the lever and half nut out of locking engagement. Furthermore since the shaft extends in a lateral direction from the carriage it would have to be operated from an awkward position under the vehicle. By the present invention these objections and criticisms are overcome.

Accordingly it is an object of this invention to provide an inexpensive jack suitable for supporting trailers or similar vehicles.

A further object of the invention is to provide a jack simple in design but one which can be securely locked in either an erected or collapsed position.

An additional object of the invention is to provide a jack reliable in operation and which is carried by a trailer in a locked collapsed position in transit and in a locked erected position when parked.

Another object of the invention is to provide a jack having an improved locking mechanism therein.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims taken in conjunction with the accompanying drawing, in which:

FIGURE 1 is a side elevational view of the invention in an erected position.

FIGURE 2 is an end elevational view of the present invention taken from the handle end thereof.

FIGURE 3 is a cross sectional view of the invention taken along the lines 3-3 of FIGURE 1.

FIGURE 4 is a sectional view along the lines 4 4 of FIGURE 3.

Broadly the invention comprises a jack used principally for supporting trailers and the like when they are not in transit. It comprises an operating screw with a carriage or trunnion slide adapted to move freely therealong. A base leg is pivotally connected to the carriage and Supporting struts are pivotally connected to both the carriage and to a mounting structure positioned on the trailer.

Inside the carriage, a half nut is positioned to engage the screw. A shaft is rotatably mounted in a horizontal fashion just underneath and parallel to the screw and extends longitudinally through the carriage. The portion of the shaft adjacent the screw is formed with a cut-away portion. Since the shaft is adapted to bear against the half nut, it will force the said half nut either into or out of engagement with the screw.

Thus when the half nut rides on the cut-away portion of the shaft, the said half nut is not engaged with the screw allowing the carriage to be moved to any position on the screw, which in turn will either erect or collapse the leg and supporting struts. However when the converse is true and the half nut rides on the cylindrical portion of the shaft, it is operatively engaged with the screw and the carriage can only be moved by rotating the said screw.

In greater detail and with reference to the drawings, the apparatus comprises a bearer bar 10 adapted to be secured to the underside of a trailer. The bearer bar is designed to have down turned end lugs 12 which form journal bearings 14 in which are rotatably positioned the ends of the horizontally disposed screw 16. The inner end of the screw 1,6 projects beyond the lug 12 and has secured thereto the nut 18. The opposite end of screw 16 extends beyond the lug 12 as a shaft-like structure and has a handle 19 attached at its outer end.

The carriage 20 is slidably mounted on the screw 16. It includes a tubular portion 21 having a bore diameter equivalent to the diameter of the screw thread enabling the said carriage 20 to slide freely thereon. A pair of parallel flanges 23 integral with the tubular portion 21 extend in a downward manner from each side of said tubular portion. Y

Positioned in the carriage 20 between the parallel ilanges 23 is a half nut 22. It operates as a worm gear and is adapted to slide into or out of engagement with the screw 16. Thus, since the half nut 22 is positioned within the carriage 20, it functions to either engage or disengage the said carriage 20 with the screw 16. The shaft 24 also extends horizontally through the lower portion of carriage 20 between the flanges 23 and is disposed in a parallel manner beneath the screw 16. The ends of said shaft are rotatably positioned in the lugs 12 which form journal bearings 25 therefor. The inner end of said shaft 24 extends slightly beyond the lug 12 and is secured by a cotter pin 26. A pin 28 is positioned in the shaft 24 near the inner end thereof just prior to its contact with lug 12, said pin 28 being adapted to contact a peg 30 positioned on the adjacent lug 12 thereby restricting the rotational movement of the shaft. The opposite end of the shaft 24 extends substantially beyond the adjacent lug 12 and has a handle 32 attached thereto.

The shaft 24 contains a cut-away portion 34 disposed along the entire length of the screw 16 positioned thereabove. The spring 36 is positioned around and connected at one end to the shaft 24 adjacent the lug 12 and extends to an operative connection of the opposite end thereof on the shaft-like structure of screw 16. The spring 36 is so positioned as to constantly urge the cylindrical portion of shaft 24 to bear against the nut 22 forcing the same into worm engagement with the screw 16.

A leg 40 is pivotally connected at 41 to each side of the carriage 20 and contains a foot 42 integrally positioned on its lower end. A pair of'struts 44 and 45 are pivotally attached to the leg 40 at the intermediate positions 46 and 47, respectively. The struts 44 and 4S are also pivotally connected at 48 and 49 respectively to the end lugs 50 which are formed on the ends of bracket 52. The said bracket 52 is mounted near one end thereof to the outer end of the bearer bar 10.

Thus, to move the apparatus to an inoperative position the shaft 24 is rotated so that the cut-away portion 34 bears on the half nut 22 permitting the said half nut to slide out of engagement with the screw 16 thereby allowing the carriage 20 to freely slide along the screw 16 to an inward position lifting the leg 40 and struts 44 and 45 respectively to a horizontal or collapsed position. At this point the shaft 24 is released allowing the spring 36 to rotate the cylindrical portion 38 of the shaft so as to bear on the half nut 22 forcing the same into engagement with the screw 16 and thereby locking the leg in its inoperative position.

It is clear then that to move the apparatus from an inoperative to an operative position, the shaft 24 is rotated to allow the cut-away portion 34 to bear on the half nut 22 permitting the said half nut to slide out of engagement with the screw 16 and then moving the carriage 20 to a position near the opposite or outer end of the screw 16. This pivots the leg 40 and the struts 44 and 4S downward to the operative position. The shaft 24 is then released and as stated previously the spring 36 rotates the shaft 38 so that the cylindrical portion bears on the half nut 22 forcing it into engagement with the screw 16 thus locking the leg in its operative position. The screw may be additionally rotated when the half nut is in position if any further required adjustments of the operational position of the apparatus are needed.

It is pointed out that the jack described herein has no lever arrangement as described in applicants prior British Patent 890,651. The present invention employs the direct contact of the cylindrical portion of the shaft 24 on the half nut 22 to force the same into locking engagement with the screw 1-6 whereas the prior patent describes a lever `between said shaft 24 and said half nut 22. Furthermore in the present invention, the shaft 24 extends horizontally through the carriage 20 and parallel to the screw 16 rather than protruding into one side of the carriage 20 and extending in a lateral direction relative to the screw 16. It has been found that such an arrangement greatly enhances the strength and reliability of the invention. An additional difference is that the present invention employs the spring 36 positioned between the shaft 24 and the shaft-like portion of the screw 16 as the force for constantly urging the half nut 22 into engagement with screw 16.

Although the invention has been described with a certain degree of particularity it is understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.

What is claimed is:

1. In a jack assembly for moving a base leg structure from an inoperative to an operative position having a mounting bar for securing to a vehicle, a screw rotatably journalled on said mounting bar and retained against axial displacement, a carriage positioned on said screw and adapted to slide therealong, a base leg member pivotally connected to said carriage, a pair of links pivotally connected at one end to said leg and at the other end to said mounting bar, said links adapted to support said base leg member, a freely slidable nut positioned in said carriage and adapted to slide into and out of an operative position with said screw and a device to hold the nut in said operative position with the said screw, the improvement comprising a shaft horizontally positioned Ibeneath and parallel to said screw and rotatably journalled in said mounting bar, said shaft adapted to bear directly on said nut and force the same in a sliding movement into and out of operative engagement with said screw.

2. In a jack assembly for moving a base leg structure from an inoperative to an operative position having a mounting bar for securing to a vehicle, a screw rotatably journalled on said mounting bar and retained against axial displacement, a carriage positioned on said screw and adapted to slide therealong, a base leg member pivotally connected to said carriage, a pair of links pivotally connected at one end to said leg member and at the other end to said mounting bar, said links adapted to support said rbase leg member, a freely slidable nut positioned in said carriage and adapted for sliding movement into and out of operative position with said screw and a device to hold the nut in said operative position with the said screw, the improvement comprising a shaft horizontally positioned beneath and parallel to said screw and rotatably journalled in said mounting bar, said shaft bearing directly on the `said nut and having both a cut-away portion and a cylindrical portion adjacent said screw, the cylindrical portion of the shaft adapted to force the said nut in a sliding movement into locking engagement with said screw and said cut-away portion adapted to release said nut in a sliding movement out of locking engagement with said screw.

3. In a jack assembly for moving a base leg structure from an inoperative to an operative position having a mounting bar for securing to a vehicle, a screw rotatably journalled on said mounting bar and retained against axial displacement, the outer end of said screw extending substantially beyond the mounting bar, a carriage positioned on said screw and adapted to slide therealong, a base leg member pivotally connected to said carriage, a pair of links pivotally connected at one end to said leg and at the other end to said mounting bar, said links adapted to support said base leg member, a freely slidable nut positioned in said carriage and adapted for sliding movement into and out of an inoperative position with said screw and a device to hold the nut in said operative position with said screw, the improvement comprising a shaft horizontally positioned beneath and parallel to said screw rotatably journalled in said mounting bar with the outer end thereof extending substantially beyond the mounting bar, said shaft adapted to bear directly on said nut and force the same in a sliding movement into and out of operative engagement with said screw.

4. In a jack assembly for moving a base leg structure from an inoperative to an operative position having a.

mounting bar for securing to a vehicle, a screw rotatably journalled on said mounting bar and retained against axial displacement, the outer end of said screw extending substantially beyond the mounting bar, a carriage positioned on said screw and adapted to slide therealong, a base leg member pivotally connected to said carriage, a pair of links pivotally connected at one end to said leg member and at the other end to said mounting bar, said links adapted to support said base leg member, a freely slidable nut positioned in said carriage and adapted for sliding movement into and out of an operative position with said screw and a device to hold the nut in said operative position with the said screw, the improvement comprising a shaft horizontally positioned beneath and parallel to said screw rotatably journalled in said mounting bar with the outer end thereof extending substantially beyond the mounting bar, said shaft bearing directly on said nut and having 4both a cut-away portion and a cylindrical portion adjacent said screw, the cylindrical portion of said shaft adapted to force the said nut in a sliding movement into locking engagement with said screw and the cut-away portion adapted to release said nut in a sliding movement out of locking engagement with said screw.

5. In a jack assembly for moving a base leg structure from an inoperative to an operative position having a mounting bar for securing to a vehicle, a screw rotatably journalled on said mounting bar and retained against axial displacement, one end of said `screw extending substantially beyond the mounting bar, a carriage positioned on said `screw and adapted to slide therealong, a base leg member pivotally connected to said carriage, a pair of links pivotally connected at one end to said leg member and at the other end to said mounting bar, said links adapted to support said lbase leg member, a freely slidable nut positioned in said carriage and adapted for sliding movement into and out of an operative position with said screw and a device to hold the nut in said operative position with the said screw, the improvement comprising a shaft horizontally positioned beneath and parallel to said screw rotatably journalled in said mounting bar with one end thereof extending substantially beyond the mounting 20 bar, said shaft bearing directly on said nut and having both a cut-away portion and a cylindrical portion adjacent said screw, the cylindrical portion of said shaft adapted to force the said nut in a sliding movement into locking engagement with said screw and the cut-away portion adapted to release said nut in a sliding movement out of locking engagement with said screw.

6. The improved jack assembly as defined in claim 5 wherein a spring is connected at one end to said shaft and at the other end to said screw, said spring adapted to constantly urge the cylindrical portion of said shaft to bear against said nut forcing the same into operative engagement with the screw.

References Cited UNITED STATES PATENTS 3,022,043 2/1962 Weiss 254-98 FOREIGN PATENTS 890,651 3/ 1962 Great Britain.

OTHELL M. SIMPSON, Primary Examiner. 

1. IN A JACK ASSEMBLY FOR MOVING A BASE LEG STRUCTURE FROM AN INOPERATIVE TO AN OPERATIVE POSITION HAVING A MOUNTING BAR FOR SECURING TO A VEHICLE, A SCREW ROTATABLY JOURNALLED ON SAID MOUNTING BAR AND RETAINED AGAINST AXIAL DISPLACEMENT, A CARRIAGE POSITIONED ON SAID SCREW AND ADAPTED TO SLIDE THEREALONG, A BASE LEG MEMBER PIVOTALLY CONNECTED TO SAID CARRIAGE, A PAIR OF LINKS PIVOTALLY CONNECTED AT ONE END TO SAID LEG AND AT THE OTHER END TO SAID MOUNTING BAR, SAID LINKS ADAPTED TO SUPPORT SAID BASE LEG MEMBER, A FREELY SLIDABLE NUT POSITIONED IN SAID CAR- 